Department of Exercise Science, Arnold School of Public Health, University of South Carolina, 921 Assembly Street, Columbia, SC 29208, USA.
Department of Health Sciences, Saginaw Valley State University, 7400 Bay Road, University Center, MI 48710, USA.
Public Health. 2016 Mar;132:64-71. doi: 10.1016/j.puhe.2015.07.040. Epub 2015 Aug 25.
There is an implicit assumption that increased physical activity (PA) levels are responsible for the mental health benefits resulting from participation in PA programs. Other factors associated with participation may in fact be responsible. The purpose of this study was to examine whether changes in PA mediated the effects of two PA programs (Active Choices [AC] and Active Living Every Day [ALED]) on mental health outcomes.
Secondary data analyses of quasi-experimental study.
A sub-sample of older adults who participated in AC (n = 744) and ALED (n = 853) were included in the current analyses. MacKinnon's product of coefficients was used to test change in PA as a mediator of the relationship between program dose and change in mental health outcomes (depressive symptoms, stress, and number of days with poor mental health).
Change in PA explained 19% (AC) and 13% (ALED) of the absolute effects of program dose on depressive symptoms, 18% (AC) and 14% (ALED) of the effects on stress, and 37% (ALED) of the effects on days with poor mental health.
Mounting evidence from both epidemiological studies and controlled trials suggests that PA can improve mental health. This study adds that increasing PA levels may improve mental health in older adults in 'real-world' settings.
人们默认增加身体活动（PA）水平是参与 PA 项目带来心理健康益处的原因。但实际上，与参与项目相关的其他因素可能才是真正的原因。本研究旨在检验 PA 的变化是否在两种 PA 项目（积极选择[AC]和积极生活每一天[ALED]）对心理健康结果的影响中起中介作用。
准实验研究的二次数据分析。
纳入了参与 AC（n=744）和 ALED（n=853）的老年人亚组进行当前分析。使用系数乘积法检验 PA 的变化是否在项目剂量与心理健康结果变化（抑郁症状、压力和心理健康不佳天数）之间的关系中起中介作用。
PA 的变化解释了项目剂量对抑郁症状的绝对影响的 19%（AC）和 13%（ALED）、对压力的影响的 18%（AC）和 14%（ALED），以及对心理健康不佳天数的影响的 37%（ALED）。
来自流行病学研究和对照试验的越来越多的证据表明，PA 可以改善心理健康。本研究补充说，在“现实世界”环境中，增加 PA 水平可能会改善老年人的心理健康。
